Swimming Pool Heat Exchangers And Associated Systems And Methods

ABSTRACT

Exemplary embodiments are directed to swimming pool heat exchangers including a housing and one or more tube assemblies disposed within the housing. Each of the tube assemblies includes an elongated titanium tube and at least one fin welded to an outer surface of the elongated titanium tube. The elongated titanium tube and the at least one welded fin allow for corrosion resistance to swimming pool water while simultaneously allowing for improved heat transfer from the heat exchanger to the swimming pool water.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the priority benefit of U.S. ProvisionalApplication No. 62/348,186, filed Jun. 10, 2016, which is herebyincorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

The present disclosure relates to swimming pool heat exchangers andassociated systems and methods and, in particular, to heat exchangersincluding a plurality of titanium tubes with welded copper fins forimproved heat transfer in swimming pool heater applications.

BACKGROUND

Various types of heaters have been used over the years for heatingfluids in applications such as residential heating systems and swimmingpools. Although discussed herein with respect to water tube heatexchangers, fire tube heat exchangers have also been used in theindustry. Most heaters include a heat exchanger disposed proximate asource of heat through which the fluid to be heated passes. The heatexchanger generally includes a metal conduit through which the fluid tobe heated can pass and is positioned above a burning gas to absorb theheat of combustion and conduct it to the fluid passing through theconduit. To increase the efficiency of heat transfer, the heat exchangercan be configured to maximize the exterior surface area exposed to theheat of combustion by using metal fins on the conduit.

Different materials of construction for heat exchangers have been used.The advantages of using titanium tubing with swimming pool water toavoid corrosion has been well documented, and titanium tubing has beenwidely used in mechanical heating appliances (e.g., heat pumps). Inparticular, titanium has been successfully used with mechanical heatingappliances due to the heat exchanger being used for a liquid-to-liquidheat transfer and, compared to gas-fired appliances, a relatively lowamount of heat to be transferred into the swimming pool water.

Gas-fired appliances with an air-to-liquid heat exchanger generally havea higher heat capacity than liquid-to-liquid heat exchangers. However,achieving adequate heat transfer using titanium tubes in theair-to-liquid heat exchanger of a gas-fired appliance has proven elusivein the swimming pool heater industry. One hurdle to attaining adequateheat transfer is the inability to extrude titanium into a tube with asubstantial number of integrated fins. Although the extrusion process iswidely used with copper and cupro-nickel in the industry, fins for atitanium tube cannot be extruded to the desired size for proper heattransfer. Some swimming pool heat exchangers include extruded fin tubesmanufactured from either copper or cupro-nickel and have fin heightsthat cannot be manufactured out of titanium.

Some manufacturers have welded stainless steel fins to stainless steeltubing. Some industries, such as boiler and fluid processing, have usedfins of a dissimilar material than the tube welded to the titaniumtubes. Some swimming pool heat exchangers include plate fin designs withtubes mechanically expanded into collars on the plates to bond the finsand tubes. However, such methods are unfeasible for use with titanium.

Thus, a need exists for swimming pool heat exchangers that includetitanium tubes with welded copper fins that provide the desired amountof heat transfer and corrosion resistance in air-to-liquid applications.These and other needs are addressed by the swimming pool heat exchangersand associated systems and methods of the present disclosure.

SUMMARY

In accordance with embodiments of the present disclosure, exemplaryswimming pool heat exchangers are provided that include a housing andone or more tube assemblies disposed within the housing. Each of thetube assemblies includes an elongated titanium tube and at least one finwelded (e.g., laser welded) to an outer surface of the elongatedtitanium tube. In some embodiments, any type of welding can be used toattach the fins to the outer surface of the titanium tube. In someembodiments, the tube assemblies can include a plurality of finsindividually welded in a spaced manner along the outer surface of theelongated titanium tube. In some embodiments, the tube assemblies caneach include one fin fabricated as a single material and defining ahelical shape such that the inner surface of the helical fin iscontinuously welded along the outer surface of the elongated titaniumtube. The elongated titanium tube and the welded fin(s) allow forcorrosion resistance to swimming pool water while simultaneouslyallowing for improved heat transfer from the heat exchanger to theswimming pool water.

The at least one fin can be a copper fin. The at least one fin candefine a circular configuration. The elongated titanium tube can definea cylindrical configuration with an inner passage extendingtherethrough. The heat exchanger can include at least one tube sheetsecured to ends of the one or more tube assemblies.

In some embodiments, the heat exchanger can include a column of the tubeassemblies aligned along a central axis. In some embodiments, the heatexchanger can include a plurality of the tube assemblies staggeredrelative to each other. In some embodiments, the one or more tubeassemblies can be of the same outer diameter. In some embodiments, theone or more tube assemblies can be of different outer diameters. In someembodiments, the one or more tube assemblies can be arranged in, e.g., aU-shaped or cylindrical configuration, a flat configuration defining asingle column of tube assemblies, a bent spiral configuration, acylindrical configuration including a passage extending between the tubeassemblies, an A-shaped configuration, a V-shaped configuration, a solidblock configuration including multiple rows and columns of tubeassemblies disposed adjacent to each other, combinations thereof, or thelike.

In accordance with embodiments of the present disclosure, an exemplarymethod of heating swimming pool water is provided. The method includesintroducing heated gas (or an alternative source) into one of theexemplary heat exchangers disclosed herein. In particular, the heatedgas can be introduced into an area surrounding the one or more tubeassemblies. The method includes introducing or circulating swimming poolwater to the one or more tube assemblies of the heat exchanger to allowfor heat transfer between the heated gas and the swimming pool water.The method includes adjusting a configuration of the one or more tubeassemblies within the housing to adjust a heat transfer rate to theswimming pool water.

In accordance with embodiments of the present disclosure, an exemplaryheat exchanger system is provided that includes a heat exchanger asdisclosed herein, a gas source, and a swimming pool water source. Thegas source can be fluidly connected to the heat exchanger and configuredto supply heated gas (or an alternative source) to an area surroundingthe one or more tube assemblies. The swimming pool water source can befluidly connected to the heat exchanger and configured to supplyswimming pool water to the one or more tube assemblies.

Other objects and features will become apparent from the followingdetailed description considered in conjunction with the accompanyingdrawings. It is to be understood, however, that the drawings aredesigned as an illustration only and not as a definition of the limitsof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

To assist those of skill in the art in making and using the disclosedheat exchangers and associated systems and methods, reference is made tothe accompanying figures, wherein:

FIG. 1 is a diagrammatic side view of an exemplary tube assembly of anexemplary heat exchanger according to the present disclosure.

FIG. 2 is a diagrammatic front view of an exemplary tube assembly ofFIG. 1.

FIG. 3 is a perspective view of a plurality of exemplary tube assembliesof FIG. 1.

FIG. 4 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 5 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 6 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 7 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 8 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 9 is a front view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1.

FIG. 10 is a front view of an exemplary heat exchanger including onecolumn of a plurality of tube assemblies of FIG. 1.

FIG. 11 is a front view of an exemplary heat exchanger including twocolumns of a plurality of tube assemblies of FIG. 1.

FIG. 12 is a front view of an exemplary heat exchanger including threecolumns of a plurality of tube assemblies of FIG. 1.

FIG. 13 is a front view of an exemplary heat exchanger including twocolumns of a plurality of differently sized tube assemblies of FIG. 1.

FIG. 14 is a front view of an exemplary heat exchanger including onestaggered column of a plurality of tube assemblies of FIG. 1.

FIG. 15 is a front view of an exemplary heat exchanger including twostaggered columns of a plurality of tube assemblies of FIG. 1.

FIG. 16 is a front view of an exemplary heat exchanger including threestaggered columns of a plurality of tube assemblies of FIG. 1.

FIG. 17 is a front view of an exemplary heat exchanger including twostaggered columns and one aligned column of a plurality of differentlysized tube assemblies of FIG. 1.

FIG. 18 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a horizontal cylindricalconfiguration.

FIG. 19 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a horizontal flatconfiguration.

FIG. 20 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a vertical flat configuration.

FIG. 21 is a perspective view of an exemplary heat exchanger including atube assemblies of FIG. 1 in a spiral configuration.

FIG. 22 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a vertical cylindricalconfiguration.

FIG. 23 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a flat A-shaped configuration.

FIG. 24 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a flat slanted configuration.

FIG. 25 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a solid block configuration.

FIG. 26 is a perspective view of an exemplary heat exchanger including aplurality of tube assemblies of FIG. 1 in a flat slanted configuration.

FIG. 27 is a block diagram of an exemplary heat exchanger systemaccording to the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In accordance with embodiments of the present disclosure, exemplary heatexchangers including a plurality of tubes with welded fins (e.g., laserwelded) are provided. The tubes can be smooth titanium tubes thatinclude copper fins welded to the exterior surface to enhance heattransfer from hot combustion gases to swimming pool water flowing withinthe heat exchanger tubes of a gas-fired pool heater. In someembodiments, the heat exchanger can include a single welded fin tubeattached to a water circulating system suspended over a small source ofheat. The exemplary heat exchangers achieve improved heat transfer byusing titanium tubes with the welded copper fins in an air-to-liquidheat exchanger system with corrosion resistance (normally found in heatpump heat exchangers) and with a higher heat capacity of gas-firedappliances. In particular, the exemplary heat exchangers includetitanium tubes in gas-fired swimming pool heaters to achieve corrosionresistance by isolating the swimming pool water within the titaniumtubes, while maintaining the heat transfer characteristics ofhigh-finned heat exchanger tubes.

By using titanium tubes with fins welded to the exterior made fromcopper or another material, heat transfer far above what titanium tubescan achieve alone can be accomplished while still offering the corrosionresistance needed in the portion of the heat exchanger in direct contactwith swimming pool water. In particular, rather than using extruded orexpanded fins as normally done in the swimming pool heater industry, thefins are welded to the titanium tube to facilitate the higher heattransfer than normally achieved by the titanium tubes alone. The weldedfins, which provide a significant increase in surface area and aremanufactured from a material with a higher thermal conductivity thantitanium, thereby transferring the required amount of heat from a heatsource, typically a burner, to swimming pool water inside of thetitanium tube. The titanium tube, in turn, is resistant to corrosiontypically caused by exposure to swimming pool water. This heat transferis aided by the fact that the entire length of fin is welded to thetube, resulting in a permanent thermal bond between the titanium tubeand the fins. The bond would not be permanent if the fin was onlyattached at the endpoints or only by mechanical means. Therefore, thethermal bond between the titanium tube and the fins results in animproved attachment between the components.

Although discussed herein with respect to gas-fired swimming poolheaters, it should be understood that the exemplary heat exchangers canbe used with any appliance that includes a heat exchanger configured totransfer heat from hot combustion gases to liquid where corrosion causedby the liquid is one of the primary concerns. In some embodiments, theexemplary tubes and fins can be used in heaters for fluids, such as theheater for fluids disclosed in U.S. Pat. No. 6,026,804, incorporatedherein by reference. In some embodiments, rather than laser welding, thetitanium tube can be expanded into the plate fins. However, such methodsare generally performed with larger and more complicated processingmachines.

A plurality of titanium tubes can be arranged to form a heat exchangerand can be secured to one or more tube sheets to define the heatexchanger shape. The tube sheets provide a transition to the connectedwater system. In some embodiments, different geometries, configurationsor arrangements of the heat exchanger can be used, resulting indifferent tube arrangements within the geometry and different airflowpaths through the tubes. In some embodiments, varying sizes and/ornumbers of the tubes can be used in flat horizontal or alternativeconfigurations to differ airflow paths through the tubes.

In some embodiments, the material of the base tubing or the welded fins,or the geometry or arrangement of the fins relative to the tubes can bechanged. Changing the fins, e.g., the height, material, fin density onthe tube, combinations thereof, or the like, can allow for heat transferat different rates. Thus, by changing characteristics of the fins weldedto the tubes, the heat exchanger can be customized to adjust for thedesired heat transfer rate. Changing the tube material can be used toaccommodate for different types or sources of corrosion present in theheat exchanger system.

With reference to FIGS. 1 and 2, diagrammatic side and front views of anexemplary tube assembly 100 of an exemplary heat exchanger are provided.It should be understood that the heat exchanger can include one or moreof the tube assemblies 100 arranged in various configurations dependingon the heat transfer rate desired for the system. Each tube assembly 100includes an elongated tube 102, e.g., an extruded titanium tube defininga cylindrical configuration with an inner passage 103 extendingtherethrough configured to receive swimming pool water. In someembodiments, the tube 102 can define a configuration other thancylindrical, e.g., square, rectangular, oval, or the like. The tube 102can define an overall length 104 extending along a central longitudinalaxis 106. The tube 102 can define an outer diameter 108 with a wallthickness 110. In some embodiments, the outer diameter 108 can beapproximately 0.75 inches and the wall thickness 110 can beapproximately 0.02 inches.

The tube assembly 100 includes a plurality of fins 112 (e.g., copperfins) secured to an outer surface 116 of the tube 102. The fins 112 canbe welded (e.g., laser welded) to the outer surface 116 of the tube 102.In particular, rather than only a partial welding, the entirecircumferential inner diameter of the fins 112 can be laser welded tothe outer surface 116 of the tube 102. In some embodiments, the fins 112can define a substantially circular configuration with a diameter 114.In some embodiments, the diameter 114 of each fin 112 can beapproximately, e.g., 40 mm, 50 mm, or the like. In some embodiments,each fin 112 can define a thickness between approximately 0.015 inchesto approximately 0.020 inches. In some embodiments, the plurality offins 112 can be fabricated as a single piece of material helically woundaround the outer surface 116 of the tube 102 and welded along the entirecontact surface of the inner surface of the fins 112 and the outersurface 116 of the tube 102. Although illustrated as substantiallycircular, in some embodiments, the fins 112 can define differentconfigurations, e.g., oval, rectangular, square, triangular, hexagonal,or the like. In some embodiments, fins 112 having multiple differentconfigurations can be secured to the outer surface 116 of the tube 102.For example, rather than being symmetrical relative to the vertical andhorizontal central axes 128, 130 as shown in FIG. 2, the fins 112 candefine an asymmetrical configuration.

In some embodiments, the fins 112 can be spaced substantially uniformlyrelative to each other along the tube 102. In some embodiments, thespacing between the fins 112 can be different. In some embodiments, thefins 112 can be welded to the tube 102 such that the fins 112 extendsubstantially perpendicularly relative to the longitudinal axis 106. Insome embodiments, the fins 112 can be welded to the tube 102 atnon-perpendicular angles relative to the longitudinal axis 106. The fins112 can extend only along a partial length 118 of the overall length 104of the tube 102. In particular, the proximal end 120 and the distal end122 of the tube 102 can remain uncovered (e.g., without fins 112). Forexample, a proximal length 124 and a distal length 126 of the tube 102can remain uncovered or exposed. In some embodiments, the proximal anddistal lengths 124, 126 can be substantially similar in dimension. Insome embodiments, the proximal and distal lengths 124, 126 can bedifferent in dimension.

FIG. 3 shows a plurality of tube assemblies 100 positioned adjacent toeach other. As shown in FIG. 3, the tube assemblies 100 can be alignedalong the longitudinal axis 106 of each tube assembly 100 to form asubstantially planar configuration of a heat exchanger. Alternativeconfigurations or arrangements of the tube assemblies 100 will bediscussed in greater detail below.

FIGS. 4-9 show front views of exemplary heat exchangers 150 a-f withdifferent configurations or arrangements of the tube assemblies 100(referred to as primary tube assemblies 100 a and secondary tubeassemblies 100 b). The diameter of the tube assemblies 100 defines thediameter of the fins of each respective tube assembly 100. The tubeassemblies 100 a, 100 b can be arranged in a pattern relative to eachother and secured on opposing sides (e.g., the proximal and distal ends120, 122) by endplates or tube sheets. In particular, FIGS. 4-9 showdifferent sizes and arrangements of the tube assemblies 100 that can fitwithin the same structure 152 that defines a height 154 and a width 156.For example, different sizes and combinations of the tube assemblies 100can be used to fit within a structure 152 that defines the width 156. Itshould be understood that the tube assemblies 100 of FIGS. 4-9 caninclude tube sheets disposed on each side of the tube assemblies 100 a,100 b. In some embodiments, the tube sheets can define a substantiallyrectangular configuration.

In the embodiment of FIG. 4, the primary tube assemblies 100 a can bealigned along the horizontal central axis 130. The primary tubeassemblies 100 a can be spaced relative to each other to receive thesecondary tube assemblies 100 b therebetween. In particular, thesecondary tube assemblies 100 b can be disposed between the primary tubeassemblies 100 a in a staggered or offset manner in a diagonaldirection. The secondary tube assemblies 100 b are therefore alignedalong their respective horizontal central axes, with the horizontalcentral axis of the secondary tube assemblies 100 b being offset fromthe horizontal central axis 130 of the primary tube assemblies 100 a. Asan example, the heat exchanger 150 a can include six tube assemblies 100a, 100 b. The fins of the tube assemblies 100 a, 100 b can be orientedsubstantially tangent relative to each other to avoid bypassedcombustion gasses from escaping the heat exchanger. In some embodiments,each of the tube assemblies 100 a, 100 b can be spaced relative to eachother such that no tube assemblies 100 a, 100 b are positioned directlyagainst each other. In some embodiments, the fins of the tube assemblies100 a, 100 b can be positioned adjacent to each other in an abuttingrelationship.

The heat exchanger 150 b of FIG. 5 can be substantially similar instructure and function to the heat exchanger 150 a of FIG. 4, exceptthat seven tube assemblies 100 a, 100 b can be used. In particular, theouter diameter of the fins of the tube assemblies 100 a, 100 b can bedimensioned smaller than the tube assemblies 100 a, 100 b of FIG. 4,allowing a greater number of tube assemblies 100 a, 100 b to fit withinthe same width 156 of the structure 152.

The heat exchanger 150 c of FIG. 6 can be substantially similar instructure and function to the heat exchanger of 150 a of FIG. 4, exceptthat ten tube assemblies 100 a, 100 b can be used. In particular, theouter diameter of the fins of the tube assemblies 100 a, 100 b can bedimensioned smaller than the tube assemblies 100 a, 100 b of FIGS. 4 and5, allowing a greater number of tube assemblies 100 a, 100 b to fitwithin the same width 156 of the structure 152.

The heat exchanger 150 d of FIG. 7 can be substantially similar instructure and function to the heat exchanger 150 a of FIG. 4, exceptthat sixteen tube assemblies 100 a, 100 b can be used. In particular,the outer diameter of the fins of the tube assemblies 100 a, 100 b canbe dimensioned smaller than the tube assemblies 100 a, 100 b of FIGS.4-6, allowing a greater number of tube assemblies 100 a, 100 b to fitwithin the same width 156 of the structure 152.

The heat exchanger 150 e of FIG. 8 can be substantially similar instructure and function to the heat exchanger 150 a of FIG. 4, exceptthat fourteen tube assemblies 100 a, 100 b can be used. In particular,the outer diameter of the fins of the tube assemblies 100 a, 100 b canbe dimensioned smaller than the tube assemblies 100 a, 100 b of FIGS.4-6, allowing a greater number of tube assemblies 100 a, 100 b to fitwithin the same width 156 of the structure 152.

The heat exchanger 150 f of FIG. 9 can be substantially similar instructure and function to the heat exchanger 150 a of FIG. 4, exceptthat twelve tube assemblies 100 a, 100 b can be used. In particular, theouter diameter of the fins of the tube assemblies 100 a, 100 b can bedimensioned smaller than the tube assemblies 100 a, 100 b of FIGS. 4-6,allowing a greater number of tube assemblies 100 a, 100 b to fit withinthe same width 156 of the structure 152.

FIGS. 10-17 are front views of exemplary heat exchangers 200 a-hincluding a plurality of tube assemblies 100 arranged in differentconfigurations. Each configuration provides a variation in heat transferflow rates from the combustion gas to the swimming pool water. Inparticular, the different configurations result in varied heat transfereither by affecting the surface area in contact with the combustiongases (e.g., the number of rows and diameter of the tube assemblies 100)or by affecting the airflow pattern and distance the combustion gasesstay in contact with the heat exchanger (e.g., staggered rows anddiameter of the tube assemblies 100). For example, FIG. 10 shows a heatexchanger 200 a that includes a single column 204 of tube assemblies 100of the same size (e.g., four tube assemblies). The tube assemblies 100can be arranged to align along a vertical central axis 202. Air flow canenter the heat exchanger 200 a from, e.g., a first direction 206substantially perpendicular to the vertical central axis 202, a seconddirection 208 substantially aligned with the vertical central axis 202,combinations thereof, or the like.

FIG. 11 shows a heat exchanger 200 b that includes two columns 204 a,204 b of tube assemblies 100 of the same size (e.g., each columnincluding four tube assemblies). The tube assemblies 100 can be arrangedsuch that four tube assemblies 100 are aligned along a first verticalcentral axis 202 a and four tube assemblies 100 are aligned along asecond vertical central axis 202 b, the first and second verticalcentral axes 202 a, 202 b being spaced from each other. The two columns204 a, 204 b of the tube assemblies 100 can be disposed adjacent to eachother. Further, the adjacently positioned tube assemblies 100 can bealigned along horizontal central axes 210 a-d. Air flow can enter theheat exchanger 200 b from, e.g., a first direction 206 substantiallyperpendicular to the first and second vertical central axes 202 a, 202b, a second direction 208 substantially aligned with the first andsecond vertical central axes 202 a, 202 b, combinations thereof, or thelike.

FIG. 12 shows a heat exchanger 200 c that includes three columns 204 a-cof tube assemblies 100 of the same size (e.g., each column includingfour tube assemblies). The tube assemblies 100 can be arranged such thatfour tube assemblies 100 are aligned along a first vertical central axis202 a, four tube assemblies 100 are aligned along a second verticalcentral axis 202 b, and four tube assemblies 100 are aligned along athird vertical central axis 202 c, the vertical central axes 202 a, 202b, 202 c being spaced from each other. The three columns 204 a-c of thetube assemblies 100 can be disposed adjacent to each other. Further, theadjacently positioned tube assemblies 100 can be aligned alonghorizontal central axes 210 a-d. Air flow can enter the heat exchanger200 c from, e.g., a first direction 206 substantially perpendicular tothe vertical central axes 202 a-c, a second direction 208 substantiallyaligned with the vertical central axes 202 a-c, combinations thereof, orthe like.

FIG. 13 shows a heat exchanger 200 d that includes two columns 204 a,204 b of tube assemblies 100 a, 100 b of different sizes. The tubeassemblies 100 a of the same size can be arranged such that four tubeassemblies 100 a are aligned along a first vertical central axis 202 a,and two tube assemblies 100 b of a size different from the tubeassemblies 100 a are aligned along a second vertical central axis 202 b.The first and second vertical central axes 202 a, 202 b are spaced fromeach other. In some embodiments, the each tube assembly 100 b can beapproximately double in diameter as compared to each tube assembly 100a. The two columns 204 a, 204 b of the tube assemblies 100 a, 100 b canbe disposed adjacent to each other. A horizontal central axis 212 a ofone of the tube assemblies 100 b can be aligned between the horizontalcentral axes 210 a, 210 b of the tube assemblies 100 a. Similarly, ahorizontal central axis 212 b of the other tube assembly 100 b can bealigned between the horizontal central axes 210 c, 210 d of the tubeassemblies 100 a. Air flow can enter the heat exchanger 200 d from,e.g., a first direction 206 substantially perpendicular to the verticalcentral axes 202 a, 202 b, a second direction 208 substantially alignedwith the vertical central axes 202 a, 202 b, a third direction 214substantially perpendicular to the vertical central axes 202 a, 202 band opposing the first direction 206, combinations thereof, or the like.

FIG. 14 shows a heat exchanger 200 e that includes one staggered column204 of tube assemblies 100 of the same size (e.g., the column includingfour tube assemblies). The tube assemblies 100 can be arranged such thatevery other tube assembly 100 is aligned along a first vertical centralaxis 202 a and a second vertical central axis 202 b, respectively. Thefirst and second vertical central axes 202 a, 202 b are spaced from eachother. Each of the adjacently positioned tube assemblies 100 can bestaggered by an angle relative to horizontal central axes 210 a-d. Thefins of the tube assemblies 100 can be disposed in a substantiallytangent and abutting configuration. Air flow can enter the heatexchanger 200 e from, e.g., a first direction 206 substantiallyperpendicular to the vertical central axes 202 a, 202 b, a seconddirection 208 substantially aligned with the vertical central axes 202a, 202 b, combinations thereof, or the like.

FIG. 15 shows a heat exchanger 200 f that includes two staggered columns204 a, 204 b of tube assemblies 100 of the same size (e.g., each columnincluding four tube assemblies). The tube assemblies 100 can be arrangedsuch that every other tube assembly 100 is aligned along a first tofourth vertical central axes 202 a-d, with two tube assemblies 100aligned per vertical central axis 202 a-d. The vertical central axes 202a-d are spaced from each other. Each of the adjacently positioned tubeassemblies 100 can be staggered by an angle relative to horizontalcentral axes 210 a-d. The fins of the tube assemblies 100 can bedisposed in a substantially tangent and abutting configuration. Forexample, the fins of the tube assemblies 100 aligned along thehorizontal central axes 210 a-d can abut each other. Air flow can enterthe heat exchanger 200 f from, e.g., a first direction 206 substantiallyperpendicular to the vertical central axes 202 a-d, a second direction208 substantially aligned with the vertical central axes 202 a-d,combinations thereof, or the like.

FIG. 16 shows a heat exchanger 200 g that includes three staggeredcolumns 204 a-c of tube assemblies 100 of the same size (e.g., eachcolumn including four tube assemblies). The tube assemblies 100 can bearranged such that every other tube assembly 100 is aligned along afirst to sixth vertical central axes 202 a-f, with two tube assemblies100 aligned per vertical central axis 202 a-f. The vertical central axes202 a-f are spaced from each other. Each of the adjacently positionedtube assemblies 100 can be staggered by an angle relative to horizontalcentral axes 210 a-d. The fins of the tube assemblies 100 can bedisposed in a substantially tangent and abutting configuration. Forexample, the fins of the tube assemblies 100 aligned along thehorizontal central axes 210 a-3 can abut each other. Air flow can enterthe heat exchanger 200 g from, e.g., a first direction 206 substantiallyperpendicular to the vertical central axes 202 a-f, a second direction208 substantially aligned with the vertical central axes 202 a-f,combinations thereof, or the like.

FIG. 17 shows a heat exchanger 200 h that includes one staggered column204 a of tube assemblies 100 a of the same size (e.g., the columnincluding four tube assemblies) and one column 204 b of tube assemblies100 b sized differently than the tube assemblies 100 a. The tubeassemblies 100 a can be arranged such that every other tube assembly 100is aligned along a first vertical central axis 202 a and a secondvertical central axis 202 b, respectively. The first and second verticalcentral axes 202 a, 202 b are spaced from each other. Each of theadjacently positioned tube assemblies 100 a can be staggered by an anglerelative to horizontal central axes 210 a-f. The tube assemblies 100 bcan be arranged such that the two tube assemblies 100 b are alignedalong a third vertical central axis 202 c. The tube assemblies 100 b canbe aligned with respective horizontal central axes 210 b, 210 e of twotube assemblies 100 a. In some embodiments, the tube assemblies 100 bcan be disposed along horizontal central axes that are parallel to (butnot aligned with) the horizontal central axes 210 a-f). The fins of thetube assemblies 100 a, 100 b can be disposed in a substantially tangentand abutting configuration. Air flow can enter the heat exchanger 200 hfrom, e.g., a first direction 206 substantially perpendicular to thevertical central axes 202 a-c, a second direction 208 substantiallyaligned with the vertical central axes 202 a-c, a third direction 214substantially perpendicular to the vertical central axes 202 a-c andopposing the first direction 206, combinations thereof, or the like.

FIGS. 18-26 show perspective views of exemplary heat exchangers 250 a-iincluding tube assemblies 100 in different configurations. Althoughillustrated as substantially square or rectangular in cross-section, insome embodiments, the tube assemblies 100 can have a substantially roundcross-section (such as the tube assemblies of FIGS. 1-17). For example,FIG. 18 shows a heat exchanger 250 a including a plurality of tubeassemblies 100 stacked and aligned relative to each other, and bent intoa substantially U-shaped, tear-shaped or horizontal cylindricalconfiguration. The tube assemblies 100 can extend in a directionsubstantially aligned with horizontal. The ends of the tube assemblies100 can be disposed adjacent to each other and secured to a single tubesheet 252. Due to the curved shape of the tube assemblies 100, a passage254 is formed between the tube assemblies 100 and extends the height ofthe heat exchanger 250 a. Air flow can enter into the passage 254 fromabove 256 and below 258. Air flow can enter/exit the heat exchanger 250a in opposing directions 260, 262 perpendicular to the tube assemblies100.

FIG. 19 shows a heat exchanger 250 b including a plurality of tubeassemblies 100 aligned relative to each other and forming asubstantially horizontal flat configuration (e.g., a single row of tubeassemblies 100). Particularly, the tube assemblies 100 can extend in adirection substantially aligned with horizontal. The ends of the tubeassemblies 100 can be aligned and secured to tube sheets 252 a, 252 b onopposing sides of the tube assemblies 100. Air flow can enter/exit theheat exchanger 250 b in opposing directions 256, 258 perpendicular tothe tube assemblies 100.

FIG. 20 shows a heat exchanger 250 c including a plurality of tubeassemblies 100 aligned relative to each other and forming asubstantially vertical flat configuration (e.g., a single column of tubeassemblies 100). In particular, the tube assemblies 100 in the verticalconfiguration can be aligned substantially perpendicular to thealignment of the horizontal configuration, and substantiallyperpendicular to horizontal. The ends of the tube assemblies 100 can bealigned and secured to tube sheets 252 a, 252 b on opposing sides of thetube assemblies 100. Air flow can enter/exit the heat exchanger 250 c inopposing directions 256, 258 perpendicular to the tube assemblies 100.

FIG. 21 shows a heat exchanger 250 d including a single tube assembly100 curved into a spiral configuration. In particular, the tube assembly100 can be bent into a spiral shape with the ends of the tube assembly100 being secured to tube sheets 252 a, 252 b sized for only a singletube assembly 100. The spiral configuration results in a passage 254formed between the tube assembly 100 components and extending the heightof the heat exchanger 250 d. Air flow can enter/exit the heat exchanger250 d in opposing directions 256, 258 perpendicular to the tube assembly100, via a direction 260 passing through the passage 254, combinationsthereof, or the like.

FIG. 22 shows a heat exchanger 250 e including a plurality of tubeassemblies 100 disposed adjacent to each other and curved into avertical cylindrical configuration (e.g., a curved single row of tubeassemblies 100 extending substantially perpendicularly to horizontal).In particular, due to the cylindrical configuration of the tubeassemblies 100, a passage 254 is formed between the tube assemblies 100and extends the height of the heat exchanger 250 e. The ends of the tubeassemblies 100 can be aligned and secured to tube sheets 252 a, 252 b.Air flow can enter/exit the heat exchanger 250 e in opposing directions256, 258 perpendicular to the tube assemblies 100, via a direction 260passing through the passage 254, combinations thereof, or the like.

FIG. 23 shows a heat exchanger 250 f including a plurality of tubeassemblies 100 a, 100 b aligned and formed into a substantially flatA-shaped or upside down V-shaped configuration. In particular, the heatexchanger 250 f includes a first flat group of tube assemblies 100 a anda second flat group of tube assemblies 100 b that are joined at onecentral tube assembly 100. The first and second flat group of tubeassemblies 100 a, 100 b connect at the central tube assembly 100 andextend in opposing directions to form an angle 264 therebetween (e.g.,between approximately 30° and approximately 90°, or the like). Each ofthe tube assemblies 100 a, 100 b can extend substantially parallel tohorizontal. The ends of the tube assemblies 100 a, 100 b can be alignedand secured to tube sheets 252 a, 252 b on opposing sides of the tubeassemblies 100 a, 100 b. Air flow can enter/exit the heat exchanger 250f via direction 256 perpendicular to the second flat group of tubeassemblies 100 b, direction 258 perpendicular to the first flat group oftube assemblies 100 a, via direction 260 perpendicular to the centraltube assembly 100, combinations thereof, or the like.

FIG. 24 shows a heat exchanger 250 g including a plurality of tubeassemblies 100 aligned and formed into a flat slanted configuration(e.g., a single row of tube assemblies 100 each extending substantiallyparallel to horizontal, with the combined row of tube assemblies 100being slanted relative to horizontal). In particular, the tubeassemblies 100 can be disposed adjacent to each other and aligned into aflat configuration, and the heat exchanger 250 g can be slanted by anangle 264 (e.g., between approximately 30° and approximately 90°)relative to a horizontal plane 266. The ends of the tube assemblies 100can be aligned and secured to tube sheets 252 a, 252 b on opposing sidesof the tube assemblies 100. In the orientation of FIG. 24, the tubesheets 252 a, 252 b are at the sides of the heat exchanger 250 g. Airflow can enter/exit the heat exchanger 250 g via direction 256 parallelto the horizontal plane 266, via direction 258 perpendicular to thehorizontal plane 266, combinations thereof, or the like.

While the above configurations were formed from a single column of tubeassemblies 100, FIG. 25 shows a heat exchanger 250 h including aplurality of tube assemblies 100 aligned and formed into a solid blockconfiguration. In particular, the tube assemblies 100 can be disposedadjacent to each other in multiple rows and columns to form the solidblock configuration. Each of the tube assemblies 100 can extendsubstantially parallel to horizontal. It should be understood that avariety of shapes can be formed by varying the number of rows andcolumns of the heat exchanger 250 h. The ends of the tube assemblies 100can be aligned and secured to tube sheets 252 a, 252 b on opposing sidesof the tube assemblies 100. Air flow can enter/exit the heat exchanger250 h via direction 256 perpendicular to the tube assemblies 100.

FIG. 26 shows a heat exchanger 250 i including a plurality of tubeassemblies 100 aligned and formed into a flat slanted configuration(e.g., a single row of aligned tube assemblies 100, with each tubeassembly 100 extending at an angle relative to horizontal). Inparticular, the tube assemblies 100 can be disposed adjacent to eachother and aligned into a flat configuration, and the heat exchanger 250i can be slanted by an angle 264 (e.g., between approximately 30° andapproximately 90°) relative to a horizontal plane 266. The ends of thetube assemblies 100 can be aligned and secured to tube sheets 252 a, 252b on opposing sides of the tube assemblies 100. In the orientation ofFIG. 26, the tube sheets 252 a, 252 b are substantially at the top andbottom of the heat exchanger 250 i. The tube sheets 252 a, 252 b can besubstantially perpendicular to the ends of the tube assemblies 100, andangled relative to the horizontal plane 266. Air flow can enter/exit theheat exchanger 250 i via direction 256 parallel to the horizontal plane266, via direction 258 perpendicular to the horizontal plane 266,combinations thereof, or the like.

FIG. 27 is a block diagram of an exemplary heat exchanger system 300.The heat exchanger system 300 can include at least one of the exemplaryheat exchangers 302 described herein. The heat exchanger 302 includesone or more tube assemblies 304. The heat exchanger 302 can be disposedwithin a heater housing 306. A gas source 308 can be fluidly connectedto the heater housing 306 and/or the heat exchanger 302 to introduceheated gas into an area surrounding the tube assemblies 304. A watercirculating system or source 310 can be fluidly connected to the heaterhousing 306 to introduce swimming pool water into the tube assemblies304. Due to the heated gas surrounding the tube assemblies 304, theswimming pool water can be heated to the desired temperature. As notedabove, the titanium structure of the elongated tubes with the copperfins welded to the tubes provides for corrosion resistance by isolatingthe swimming pool water within the tubes, while allowing for improvedheat transfer to the swimming pool water.

While exemplary embodiments have been described herein, it is expresslynoted that these embodiments should not be construed as limiting, butrather that additions and modifications to what is expressly describedherein also are included within the scope of the invention. Moreover, itis to be understood that the features of the various embodimentsdescribed herein are not mutually exclusive and can exist in variouscombinations and permutations, even if such combinations or permutationsare not made express herein, without departing from the spirit and scopeof the invention.

What is claimed is:
 1. A heat exchanger for a swimming pool or spa,comprising: a housing; and a water heating system of one or more tubeassemblies disposed within the housing, each of the tube assembliesincluding an elongated titanium tube and at least one fin welded to anouter surface of the elongated titanium tube, wherein the water heatingsystem is configured for fluid communication with a fluid circulationline of said swimming pool or spa.
 2. The swimming pool heat exchangerof claim 1, wherein the at least one fin is a copper fin.
 3. Theswimming pool heat exchanger of claim 1, wherein the elongated titaniumtube defines a cylindrical configuration with an inner passage.
 4. Theswimming pool heat exchanger of claim 1, wherein the at least one findefines a circular configuration.
 5. The swimming pool heat exchanger ofclaim 1, comprising at least one tube sheet secured to ends of the oneor more tube assemblies.
 6. The swimming pool heat exchanger of claim 1,comprising a column of the tube assemblies aligned along a central axis.7. The swimming pool heat exchanger of claim 1, comprising a pluralityof the tube assemblies staggered relative to each other.
 8. The swimmingpool heat exchanger of claim 1, wherein the one or more tube assembliesare of the same outer diameter.
 9. The swimming pool heat exchanger ofclaim 1, wherein the one or more tube assemblies are of different outerdiameters.
 10. The swimming pool heat exchanger of claim 1, wherein theone or more tube assemblies are arranged in a U-shaped or cylindricalconfiguration.
 11. The swimming pool heat exchanger of claim 1, whereinthe one or more tube assemblies are arranged into a flat configurationdefining a single column of tube assemblies.
 12. The swimming pool heatexchanger of claim 1, wherein the one or more tube assemblies are bentinto a spiral configuration.
 13. The swimming pool heat exchanger ofclaim 1, wherein the one or more tube assemblies are arranged in acylindrical configuration including a passage extending between the tubeassemblies.
 14. The swimming pool heat exchanger of claim 1, wherein theone or more tube assemblies are arranged in an A-shaped or a V-shapedconfiguration.
 15. The swimming pool heat exchanger of claim 1, whereinthe one or more tube assemblies are arranged in a solid blockconfiguration including multiple rows and columns of tube assemblies.16. A method of heating swimming pool water, comprising: introducingheated gas into a heat exchanger, the heat exchanger including (i) ahousing, and (ii) one or more tube assemblies disposed within thehousing, each of the tube assemblies including an elongated titaniumtube and at least one fin welded to an outer surface of the elongatedtitanium tube, the heated gas being introduced into an area surroundingthe one or more tube assemblies; and introducing swimming pool water tothe one or more tube assemblies to allow for heat transfer between theheated gas and the swimming pool water.
 17. The method of claim 16,comprising adjusting a configuration of the one or more tube assemblieswithin the housing to adjust a heat transfer rate to the swimming poolwater.
 18. The method of claim 16, wherein the at least one fin is acopper fin.
 19. A heat exchanger system, comprising: a heat exchangerincluding (i) housing, and (ii) one or more tube assemblies disposedwithin the housing, each of the tube assemblies including an elongatedtitanium tube and at least one fin welded to an outer surface of theelongated titanium tube; a gas source fluidly connected to the heatexchanger and configured to supply heated gas to an area surrounding theone or more tube assemblies; and a swimming pool water source fluidlyconnected to the heat exchanger and configured to supply swimming poolwater to the one or more tube assemblies.
 20. The system of claim 19,wherein the at least one fin is a copper fin.